Type of =

[nha...@gmail.com]

Should = not have type (A --> B --> boolean) instead of (A --> A --> boolean)?

The same runtime value is able to have multiple types.

The use case is where one of the sides of the equality test has a skolemized type variable and isn't known at compile time, being dynamically discovered at some later point, and the other side is some known constant.

[Mark Tarver]

there is a variant of = which is == which does have the type  (A --> B --> boolean)

M.